Molly is the 29-year-old Head Maid at the Regency Grand Hotel. She takes intense pride in her cleaning duties and adheres to a strict moral code. While she misses her late grandmother terribly, she frequently relies on Gran's aphorisms to interpret social situations she finds confusing. She possesses an exceptional eye for detail, which proves useful when a famous guest collapses in the tearoom.

Molly's deceased grandmother remains a guiding presence in her granddaughter's mind. During Molly's childhood, Gran worked tirelessly as a maid to provide a safe home. She faced severe economic hardship and mistreatment from employers, yet she consistently responded with resilience to shield Molly from the world's harshness.

Mr. Preston is the kindly doorman at the Regency Grand Hotel who frequently shares Sunday dinners with Molly. In the past, he worked as the gatekeeper at the Grimthorpe mansion during Gran's employment there. He acts as a steadying presence for Molly, offering quiet support and financial help during difficult times.

J.D. Grimthorpe is a renowned mystery author whose sudden death at the hotel initiates the current investigation. Known for his abrasive personality and excessive demands, he alienated many people throughout his life. Flashbacks reveal his history of cruel behavior, aggressive outbursts, and poor treatment of the staff who worked in his home.

Detective Stark is the tough, no-nonsense police investigator assigned to the author's death. Having clashed with Molly during a previous murder investigation, Stark initially views the Head Maid with suspicion. She slowly begins to recognize that Molly's obsessive attention to domestic details offers genuine investigative value.

Lily is a shy Maid-in-Training who becomes overwhelmed by the intense scrutiny following the author's sudden death. Her timid nature and difficulty asserting herself remind Molly of her own childhood struggles. She frequently freezes under pressure, which makes her an easy target for aggressive hotel employees.

Cheryl is the hotel's former Head Maid, previously demoted for stealing tips and delivering substandard work. She harbors deep resentment toward management over her wages and actively attempts to undermine Molly's authority. She uses intimidation to manipulate junior staff members for her own gain.

Mr. Snow manages the Regency Grand Hotel, prioritizing its public reputation above all else. He frequently relies on Molly to maintain order among the cleaning staff while he attempts to handle the chaotic press response. He exhibits a noticeable crush on the deceased author's assistant.

Serena works as the personal assistant to the demanding mystery author, managing his schedule and public appearances. Bound by strict non-disclosure contracts, she carefully guards his personal belongings and business arrangements following his death.

Angela is a bartender at the hotel's restaurant, the Social. She enjoys true-crime podcasts and eagerly assists Molly by gathering gossip from the hotel guests and setting up informational meetings.

Beulah is a devoted member of the Ladies Auxiliary Mystery Book Society. She proudly refers to herself as the author's unofficial biographer and frequently argues with other club members about her status within the group.

Mrs. Grimthorpe is the author's wife, appearing exclusively in flashback sequences. She aggressively manages her household staff and dedicates herself entirely to protecting her husband's public image and maintaining the mansion's valuable artifacts.

Juan Manuel is Molly's boyfriend. Though physically absent for most of the story while visiting relatives, he remains a consistent source of emotional support and affection for Molly.

Gladys serves as the president of the mystery author's fan club. She takes her leadership position seriously and firmly checks any member who attempts to overstep their bounds.

Birdy is the treasurer of the fan club. She is the subject of quiet rumors suggesting she once retaliated against a critical speaker using laxatives.

Abigail is Serena's mother and the long-time secretary for Mr. Grimthorpe. She spends hours locked away in his study typing manuscript pages.

Mr. Jenkins is the gardener at the Grimthorpe estate. He acts kindly toward the young Molly, occasionally helping her bypass the strict household rules.

Ms. Cripps is Molly's childhood school principal. She insists on holding Molly back a grade due to social difficulties rather than academic failure. As a result, Gran withdraws Molly from school.